4L60 and shift kit

[SRT10KLLR]

I had my 4L60 built to handle more power and one of the improvements they did was to add a shift kit and increase the line pressure. I have read that when you have a built tranny you should zero out the adaptives and a buddy who has been tuning for years tells me that if I don't the tranny will not last because the shift kit it trying to shift fast and firm but the pcm is trying to stop it from doing so.

My question is do I have to remove the TM or is it just better to do so?

I had not done so yet because it was shifting really firm already. It would squeal the tires in the 1-2 shift at part throttle and I did not want it any firmer. But I recently put in a higher stall tq converter and now it is not so firm so I was thinking of reducing the TM a little. Mt thoughts were to lower the numbers in the "normal" mode and zero them out in the "performance" mode so that when I hit the tow/haul mode at the track it would shift faster and firmer.

[Mr. P.]

For sure zero-out the adaptives. AFA torque management, if the trans has the upgraded parts to handle the hit then go ahead and reduce if not eliminate TM, but it's completely optional. TM does not slow down the actual shift, it just causes the motor to nose over before commanding the shift sequence. A few people with trucks (heavier vehicles) keep a little TM in their daily driven tune, not so much that it makes the motor completely go limp before shifting but enough to take the edge off the 1-2 upshift. TM never kills trannies or drivetrains, it just makes performance go down the crapper when too much is applied like a crutch (aka OEM tune).

My Opinion FWIW...

Mr. P.

[joecar]

My understanding is that you have to zero out the shift time tables when running a shift kit.

[Mr. P.]

Not necessarily, a lot of guys bring them down to the 0.2 to 0.3 sec range; I'm not sure if that's in vogue now. If you zero the adaptives table the PCM (TCM) will just disable/ignore that functionality altogether and your shift release and apply speed will be totally dictated by the mechanicals & hydraulics in the tranny so whatever mods you've done in the transmission have not only got to be "right" but they've got to be coordinated well. Example, a lot of guys install the Transgo kit but as they are not into the case they do not install the improved exhausting mods, so the apply is sped up (mechanically) but the release is still a bit sluggish and if extreme you can have gear bind during the shift window, result of course is premature clutch wear - that's just one example. Finding a 4L60 guy that really knows his stuff is haaaaard, I'm still looking myself but think I've finally found someone that can help me, I've got my fingers crossed...

Mr. P.

[joecar]

Oh, ok, the shift times can be low non-zero and still work with the shift kit... cool...

[SRT10KLLR]

That is what I was hoping to do. Just lower my numbers but the tuner had told me that the built tranny would be in conflict with the tune.

The tranny is fully built with shift kit, servos, clutches etc. and has been modified with more line pressure than stock. It is a level 5 built to handle 550 RWHP in a Silverado.

I will zero out D0801 (tq reduction) and lower D1108 (shift times) to see what happens.

[jfpilla]

When I had my RPM trans installed Rodney told me not to 0 and to return all pressures, PW etc to stock.

[joecar]

When I had my RPM trans installed Rodney told me not to 0 and to return all pressures, PW etc to stock.

Hey Joe,

Did your trans guy say if you can set the desired shift times (to say 0.2 s)...?

Yes I agree with the pressure/PW tables to stock, since the shift kit was engineered around a stock calibrated trans.

Cheers,
Joe

[dc_justin]

Hey Joe,

Did your trans guy say if you can set the desired shift times (to say 0.2 s)...?

Yes I agree with the pressure/PW tables to stock, since the shift kit was engineered around a stock calibrated trans.

Cheers,
Joe

Adaptive shift learning will be in conflict with the shift kit unless extensive testing is done to find the shift timing values that the PCM "likes" at various torque input levels with stock base pressures.

[joecar]

I see, so then just leave the shift times stock also. Thanks Justin.